With this:

	git-ls-tree -d HEAD -- drivers/net/

shows only immediate subtrees of drivers/net.

	git-ls-tree -d -t HEAD -- drivers/net/

shows drivers, drivers/net and immediate subtrees of
drivers/net.

	git-ls-tree -d -r HEAD -- drivers/net/

shows drivers, drivers/net and all subtrees of drivers/net (but
not blobs).
Signed-off-by: NJunio C Hamano <junkio@cox.net>